If you want to make your home more energy efficient, the best place to start may be with a professional home-energy audit, a comprehensive analysis that assesses a home or business as a system of interrelated components with respect to energy use. Utility bills, indoor air quality, humidity/moisture problems, comfort and safety are all components that are interconnected within a dynamic process. An energy audit is an opportunity to learn what can be done to maximize the energy efficiency of your home or business, potentially lowering heating/cooling costs, while minimizing potential problems associated with indoor air quality and combustion-appliance safety.

Prices for energy audits vary by market and according to the complexity of the energy tracking and other tests performed. In general, however, they are relatively inexpensive and those prices are for an audit without a subsidy. Many utility companies offer energy-audit services, and some subsidize independent audits for as much as 75 percent of the total cost. Either way, if significant problems are identified and corrected, the audit will more than pay for itself.

On average, according to Erik Lindberg, an energy audit specialist, following the recommendations in an energy audit can result in a 25 percent to 30 percent reduction of annual energy consumption. Moreover, saving money isn't the only reason to have an energy audit performed.

In a thorough audit, four broad areas are covered:

• Health and safety of the occupants
• Building durability
• Comfort
• Energy efficiency

According to Lindberg, in most instances if the first three of the four have been addressed satisfactorily, the fourth (which encompasses monetary savings) will follow naturally. In a typical energy audit, it takes about two hours for an energy auditor to conduct a thorough inspection by looking at windows, doors, insulation levels, attic accesses, appliances, heating and air conditioning systems, etc.

Energy auditors are certified and licensed by the state in which they operate, and must follow standards and procedures established by that state. A complete audit typically includes assessment of the following:

• Building shell, including foundation, walls, windows, doors, ceiling and roof
• Heating system and water heater: tested for safety and efficiency
• Maintenance and safety practices: reviewed with respect to the homeowner, helping to fine-tune the balance between safety, comfort and energy usage
• Air tightness: tested devices using such as a blower-door test and infrared thermography. These diagnostic tools measure how well the house is sealed against penetration of outside air or "draftiness."
• Indoor air quality
• Energy-bill analysis
• Ice-dam problems
• Basement dampness
• Window condensation
• Excessive dust levels
• Dry air
• Insulation levels
• Mechanical systems
• Cost/benefit analysis

Check with your utility company for details on having an energy audit performed. They may have an energy audit program, or they may be able to provide information on services available in your area.